PHOENIX - Monsoon storms can create large dust storms that cover entire cities.
There's another danger other than poor visibility looming in those clouds -- Valley fever.
Valley fever is the infection caused by a fungus found in the dirt and soil. This year there has been 3,600 reports of Valley Fever, according to the Arizona Department of Health.
There may be more cases as the infection is sometimes hard to detect.
Spokesman Jessica Rigler said, "sixty percent of people who have Valley Fever don't even know they have it because they're not exhibiting any symptoms."
Symptoms may not show up for months, she said, but there are warning signs.
“You could have body aches, joint aches, mild fevers. But the hallmark when we start thinking Valley fever is a prolonged cough,” said Dr. Katy Mullens, who works at Phoenix Children's Hospital.
She said children, pregnant woman and those with immune deficiencies are most at risk.
She added that dust storms aren't the only way people can get sick with Valley fever.
"We're growing rapidly so there's a lot of construction and when that dust gets kicked up people can be exposed," she said.
Most cases are not deadly, but if you feel you have make have symptoms of Valley fever, contact your local doctor.
"The doctor can do a blood test on you so they'll just draw a little bit of blood and send that to the lab and that can tell you if you have Valley fever," Rigler said.
The best ways to prevent getting it are covering your nose and mouth if you have to be outside. Experts also recommend keeping a breathing mask in your car just in case.